#!/usr/bin/env python3

import uvicorn
from contextlib import asynccontextmanager
from fastapi import FastAPI, Request
from fastapi.middleware.cors import CORSMiddleware
from fastapi_cache import FastAPICache
from opentelemetry import trace
from opentelemetry.exporter.otlp.proto.http.trace_exporter import OTLPSpanExporter
from opentelemetry.instrumentation.fastapi import FastAPIInstrumentor
from opentelemetry.sdk.resources import Resource, SERVICE_NAME
from opentelemetry.sdk.trace import TracerProvider
from opentelemetry.sdk.trace.export import BatchSpanProcessor

from db import db
from dependencies import idfm_interface, redis_backend, settings
from routers import line, stop


@asynccontextmanager
async def lifespan(app: FastAPI):
    FastAPICache.init(redis_backend, prefix="api", enable=settings.cache.enable)

    await db.connect(settings.db, settings.clear_static_data)
    if settings.clear_static_data:
        await idfm_interface.startup()

    yield

    await db.disconnect()


app = FastAPI(lifespan=lifespan)

app.add_middleware(
    CORSMiddleware,
    allow_origins=["http://carrramba.adrien.run", "https://carrramba.adrien.run"],
    allow_credentials=True,
    allow_methods=["OPTIONS", "GET"],
    allow_headers=["*"],
)

# The cache-control header entry is not managed properly by fastapi-cache:
# For now, a request with a cache-control set to no-cache
# is interpreted as disabling the use of the server cache.
# Cf. Improve Cache-Control header parsing and handling
# https://github.com/long2ice/fastapi-cache/issues/144 workaround
@app.middleware("http")
async def fastapi_cache_issue_144_workaround(request: Request, call_next):
    entries = request.headers.__dict__["_list"]
    new_entries = [
        entry for entry in entries if entry[0].decode().lower() != "cache-control"
    ]

    request.headers.__dict__["_list"] = new_entries

    return await call_next(request)


app.include_router(line.router)
app.include_router(stop.router)


if settings.tracing.enable:
    FastAPIInstrumentor.instrument_app(app)

    trace.set_tracer_provider(
        TracerProvider(resource=Resource.create({SERVICE_NAME: settings.app_name}))
    )
    trace.get_tracer_provider().add_span_processor(
        BatchSpanProcessor(OTLPSpanExporter())
    )
    tracer = trace.get_tracer(settings.app_name)


if __name__ == "__main__":
    http_settings = settings.http

    config = uvicorn.Config(
        app=app,
        host=http_settings.host,
        port=http_settings.port,
        ssl_certfile=http_settings.cert,
        proxy_headers=True,
    )

    server = uvicorn.Server(config)

    server.run()